Production of Molybdenum Trioxide Nanosheets by Liquid Exfoliation and Their Application in High-Performance Supercapacitors
Production of Molybdenum Trioxide Nanosheets by Liquid Exfoliation and Their Application in High-Performance Supercapacitors
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DOI：
10.1021/cm500271u
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发表时间：
2014-02-25
影响因子：
8.6
通讯作者：
Coleman, Jonathan N.
中科院分区：
文献类型：
--
作者：
Hanlon, Damien;Backes, Claudia;Coleman, Jonathan N.
在这里，我们展示了一种简单的方法来剥离层状三氧化钼（MoO 3）微晶，得到多层MoO 3纳米片分散在溶剂中。通过在合适的溶剂存在下对MoO 3粉末进行超声处理，然后离心以除去未分散的材料来实现剥离。该方法在一系列Hildebrand溶解度参数接近21 MPa 1/2的溶剂中效果良好，与经典溶解度理论的预测一致。我们已经完全优化了这一过程，并证明了按尺寸分离所得纳米片的方法。拉曼光谱表明，剥离过程不会损坏的MoO 3。这是支持的测量表明，重新聚集的纳米片显示非常相似的光致发光散装MoO 3。然而，分散的纳米片具有明显不同的光致发光，表明剥离的单层去耦。我们已经使用液体剥离的MoO 3来制备超级电容器电极，由于MoO 3的低电导率，其具有相对低的电容（在10 mV/s下类似于2 F/g）。然而，除了超过逾渗阈值的碳纳米管产生了100倍的电容增加。一些MoO 3/纳米管复合材料在0.1 mV/s下显示出高达540 F/g的电容。这是层状金属氧化物的溶剂剥离的第一个实例。我们相信这项工作为各种层状化合物的液体剥离开辟了道路，从而产生了一系列新的溶液加工2D材料。
Here, we demonstrate a simple method to exfoliate layered molybdenum trioxide (MoO3) crystallites to give multilayer MoO3 nanosheets dispersed in solvents. Exfoliation is achieved by sonicating MoO3 powder in the presence of suitable solvents followed by centrifugation to remove undispersed material. This procedure works well in a range of solvents with Hildebrand solubility parameters close to 21 MPa1/2 and is consistent with the predictions of classical solubility theory. We have fully optimized this process and demonstrated methods to separate the resultant nanosheets by size. Raman spectroscopy suggests the exfoliation process does not damage the MoO3. This is supported by measurements showing that the reaggregated nanosheets display very similar photoluminescence to bulk MoO3. However, the dispersed nanosheets had distinctly different photoluminescence, indicating a decoupling of the monolayers on exfoliation. We have used liquid-exfoliated MoO3 to prepare supercapacitor electrodes that have relatively low capacitance (similar to 2 F/g at 10 mV/s) because of the low electrical conductivity of the MoO3. However, addition of carbon nanotubes beyond the percolation threshold yielded a 100-fold increase in capacitance. Some MoO3/nanotube composites displayed a capacitance as high as 540 F/g at 0.1 mV/s. This is the first example of solvent exfoliation of a layered metal oxide. We believe this work opens the way to liquid exfoliation of a wide range of layered compounds, leading to an array of new solution-processed 2D materials.